lkml.org 
[lkml]   [2018]   [Mar]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH v5 0/3] of: cache phandle nodes to reduce cost of of_find_node_by_phandle()
Date
From: Frank Rowand <frank.rowand@sony.com>

Create a cache of the nodes that contain a phandle property. Use this
cache to find the node for a given phandle value instead of scanning
the devicetree to find the node. If the phandle value is not found
in the cache, of_find_node_by_phandle() will fall back to the tree
scan algorithm.

Size and performance data is in patch 1/3 comments

Changes since v4:
- Add patch 2/3 "memblock: add memblock_free() alloc when
CONFIG_HAVE_MEMBLOCK is not set"
- patch 3/3 (previously 2/2): add checks for zero returned by
memblock_virt_alloc()

Changes since v3:
- of_populate_phandle_cache(): add check for failed memory allocation
- add patch 2/2 into series instead of as a standalone patch that was
dependent on patch 1/2 of this series

Changes since v2:
- add mask to calculation of phandle cache entry
- which results in better overhead reduction for devicetrees with
phandle properties not allocated in the monotonically increasing
range of 1..n
- due to mask, number of entries in cache potentially increased to
next power of two
- minor fixes as suggested by reviewers
- no longer using live_tree_max_phandle() so do not move it from
drivers/of/resolver.c to drivers/of/base.c

Changes since v1:
- change short description from
of: cache phandle nodes to reduce cost of of_find_node_by_phandle()
- rebase on v4.16-rc1
- reorder new functions in base.c to avoid forward declaration
- add locking around kfree(phandle_cache) for memory ordering
- add explicit check for non-null of phandle_cache in
of_find_node_by_phandle(). There is already a check for !handle,
which prevents accessing a null phandle_cache, but that dependency
is not obvious, so this check makes it more apparent.
- do not free phandle_cache if modules are enabled, so that
cached phandles will be available when modules are loaded



Frank Rowand (3):
of: cache phandle nodes to reduce cost of of_find_node_by_phandle()
memblock: add memblock_free() alloc when CONFIG_HAVE_MEMBLOCK is not
set
of: add early boot allocation of of_find_node_by_phandle() cache

drivers/of/base.c | 124 +++++++++++++++++++++++++++++++++++++++++++++--
drivers/of/fdt.c | 2 +
drivers/of/of_private.h | 5 ++
drivers/of/resolver.c | 3 --
include/linux/memblock.h | 4 ++
5 files changed, 131 insertions(+), 7 deletions(-)

--
Frank Rowand <frank.rowand@sony.com>

\
 
 \ /
  Last update: 2018-03-05 01:16    [W:0.236 / U:25.372 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site